A hand conversion to HTML of the original MacWord (or Word for Mac?)
document written in March 1989 and later redistributed unchanged apart from the
date added in May 1990. Provided for historical interest only. The diagrams are
a bit dotty, but available in versions linked below. The text has not been
changed, even to correct errors such as misnumbered figures or unfinished
references.

This is a local copy of the document
provided by the W3C. The content was not changed at all, I just fixed a few
incorrectly encoded characters and one typo in the note above.

This document was an attempt to persuade CERN management that a global
hypertext system was in CERN's interests. Note that the only name I had for it
at this time was "Mesh" -- I decided on "World Wide Web" when writing the code
in 1990.

Information Management: A Proposal

Tim Berners-Lee, CERN March 1989, May 1990

This proposal concerns the management of general information about
accelerators and experiments at CERN. It discusses the problems of loss of
information about complex evolving systems and derives a solution based on a
distributed hypertext system.

Overview

Many of the discussions of the future at CERN and the LHC era end with
the question - "Yes, but how will we ever keep track of such a large project?"
This proposal provides an answer to such questions. Firstly, it discusses the
problem of information access at CERN. Then, it introduces the idea of linked
information systems, and compares them with less flexible ways of finding
information.

It then summarises my short experience with non-linear text systems
known as "hypertext", describes what CERN needs from such a system, and what
industry may provide. Finally, it suggests steps we should take to involve
ourselves with hypertext now, so that individually and collectively we may
understand what we are creating.

Losing Information at CERN

CERN is a wonderful organisation. It involves several thousand people,
many of them very creative, all working toward common goals. Although they are
nominally organised into a hierarchical management structure, this does not
constrain the way people will communicate, and share information, equipment and
software across groups.

The actual observed working structure of the organisation is a multiply
connected "web" whose interconnections evolve with time. In this environment, a
new person arriving, or someone taking on a new task, is normally given a few
hints as to who would be useful people to talk to. Information about what
facilities exist and how to find out about them travels in the corridor gossip
and occasional newsletters, and the details about what is required to be done
spread in a similar way. All things considered, the result is remarkably
successful, despite occasional misunderstandings and duplicated effort.

A problem, however, is the high turnover of people. When two years is a
typical length of stay, information is constantly being lost. The introduction
of the new people demands a fair amount of their time and that of others before
they have any idea of what goes on. The technical details of past projects are
sometimes lost forever, or only recovered after a detective investigation in an
emergency. Often, the information has been recorded, it just cannot be
found.

If a CERN experiment were a static once-only development, all the
information could be written in a big book. As it is, CERN is constantly
changing as new ideas are produced, as new technology becomes available, and in
order to get around unforeseen technical problems. When a change is necessary,
it normally affects only a small part of the organisation. A local reason
arises for changing a part of the experiment or detector. At this point, one
has to dig around to find out what other parts and people will be affected.
Keeping a book up to date becomes impractical, and the structure of the book
needs to be constantly revised.

The sort of information we are discussing answers, for example,
questions like

Where is this module used?

Who wrote this code? Where does he work?

What documents exist about that concept?

Which laboratories are included in that project?

Which systems depend on this device?

What documents refer to this one?

The problems of information loss may be particularly acute at CERN, but
in this case (as in certain others), CERN is a model in miniature of the rest
of world in a few years time. CERN meets now some problems which the rest of
the world will have to face soon. In 10 years, there may be many commercial
solutions to the problems above, while today we need something to allow us to
continue.

Linked information systems

In providing a system for manipulating this sort of information, the
hope would be to allow a pool of information to develop which could grow and
evolve with the organisation and the projects it describes. For this to be
possible, the method of storage must not place its own restraints on the
information. This is why a "web" of notes with links (like references) between
them is far more useful than a fixed hierarchical system. When describing a
complex system, many people resort to diagrams with circles and arrows. Circles
and arrows leave one free to describe the interrelationships between things in
a way that tables, for example, do not. The system we need is like a diagram of
circles and arrows, where circles and arrows can stand for anything.

We can call the circles nodes, and the arrows links. Suppose each node
is like a small note, summary article, or comment. I'm not over concerned here
with whether it has text or graphics or both. Ideally, it represents or
describes one particular person or object. Examples of nodes can be

People

Software modules

Groups of people

Projects

Concepts

Documents

Types of hardware

Specific hardware objects

The arrows which links circle A to circle B can mean, for example, that
A...

depends on B

is part of B

made B

refers to B

uses B

is an example of B

These circles and arrows, nodes and links, have different significance
in various sorts of conventional diagrams:

Diagram

Nodes are

Arrows mean

Family tree

People

"Is parent of"

Dataflow diagram

Software modules

"Passes data to"

Dependency

Module

"Depends on"

PERT chart

Tasks

"Must be done before"

Organisational chart

People

"Reports to"

The system must allow any sort of information to be entered. Another
person must be able to find the information, sometimes without knowing what he
is looking for.

In practice, it is useful for the system to be aware of the generic
types of the links between items (dependences, for example), and the types of
nodes (people, things, documents..) without imposing any limitations.

The problem with trees

Many systems are organised hierarchically. The CERNDOC documentation
system is an example, as is the Unix file system, and the VMS/HELP system. A
tree has the practical advantage of giving every node a unique name. However,
it does not allow the system to model the real world. For example, in a
hierarchical HELP system such as VMS/HELP, one often gets to a leaf on a tree
such as

HELP COMPILER SOURCE_FORMAT PRAGMAS DEFAULTS

only to find a reference to another leaf: Please see

HELP COMPILER COMMAND OPTIONS DEFAULTS PRAGMAS

and it is necessary to leave the system and re-enter it. What was needed
was a link from one node to another, because in this case the information was
not naturally organised into a tree.

Another example of a tree-structured system is the uucp News system (try
'rn' under Unix). This is a hierarchical system of discussions ("newsgroups")
each containing articles contributed by many people. It is a very useful method
of pooling expertise, but suffers from the inflexibility of a tree. Typically,
a discussion under one newsgroup will develop into a different topic, at which
point it ought to be in a different part of the tree. (See Fig 1).

From mcvax!uunet!pyrdc!pyrnj!rutgers!bellcore!geppetto!duncan Thu Mar...
Article 93 of alt.hypertext:
Path: cernvax!mcvax!uunet!pyrdc!pyrnj!rutgers!bellcore!geppetto!duncan
>From: duncan@geppetto.ctt.bellcore.com (Scott Duncan)
Newsgroups: alt.hypertext
Subject: Re: Threat to free information networks
Message-ID: <14646@bellcore.bellcore.com>
Date: 10 Mar 89 21:00:44 GMT
References: <1784.2416BB47@isishq.FIDONET.ORG> <3437@uhccux.uhcc...
Sender: news@bellcore.bellcore.com
Reply-To: duncan@ctt.bellcore.com (Scott Duncan)
Organization: Computer Technology Transfer, Bellcore
Lines: 18
Doug Thompson has written what I felt was a thoughtful article on
censorship -- my acceptance or rejection of its points is not
particularly germane to this posting, however.
In reply Greg Lee has somewhat tersely objected.
My question (and reason for this posting) is to ask where we might
logically take this subject for more discussion. Somehow alt.hypertext
does not seem to be the proper place.
Would people feel it appropriate to move to alt.individualism or even
one of the soc groups. I am not so much concerned with the specific
issue of censorship of rec.humor.funny, but the views presented in
Greg's article.
Speaking only for myself, of course, I am...
Scott P. Duncan (duncan@ctt.bellcore.com OR ...!bellcore!ctt!duncan)
(Bellcore, 444 Hoes Lane RRC 1H-210, Piscataway, NJ...)
(201-699-3910 (w) 201-463-3683 (h))

Fig 1. An article in the UUCP News scheme.

The Subject field allows notes on the same topic to be linked
together within a "newsgroup". The name of the newsgroup (alt.hypertext) is a
hierarchical name. This particular note is expresses a problem with the strict
tree structure of the scheme: this discussion is related to several areas. Note
that the "References", "From" and "Subject" fields can all be used to generate
links.

The problem with keywords

Keywords are a common method of accessing data for which one does not
have the exact coordinates. The usual problem with keywords, however, is that
two people never chose the same keywords. The keywords then become useful only
to people who already know the application well.

Practical keyword systems (such as that of VAX/NOTES for example)
require keywords to be registered. This is already a step in the right
direction. A linked system takes this to the next logical step. Keywords can be
nodes which stand for a concept. A keyword node is then no different from any
other node. One can link documents, etc., to keywords. One can then find
keywords by finding any node to which they are related. In this way, documents
on similar topics are indirectly linked, through their key concepts. A keyword
search then becomes a search starting from a small number of named nodes, and
finding nodes which are close to all of them.

It was for these reasons that I first made a small linked information
system, not realising that a term had already been coined for the idea:
"hypertext".

A solution: Hypertext

Personal Experience with Hypertext

In 1980, I wrote a program for keeping track of software with which I
was involved in the PS control system. Called Enquire, it allowed one to store
snippets of information, and to link related pieces together in any way. To
find information, one progressed via the links from one sheet to another,
rather like in the old computer game "adventure". I used this for my personal
record of people and modules. It was similar to the application Hypercard
produced more recently by Apple for the Macintosh. A difference was that
Enquire, although lacking the fancy graphics, ran on a multiuser system, and
allowed many people to access the same data.

This example is basically a list, so the list of links is more important
than the text on the node itself. Note that each link has a type ("includes"
for example) and may also have comment associated with it. (The bottom line is
a menu bar.)

Soon after my re-arrival at CERN in the DD division, I found that the
environment was similar to that in PS, and I missed Enquire. I therefore
produced a version for the VMS, and have used it to keep track of projects,
people, groups, experiments, software modules and hardware devices with which I
have worked. I have found it personally very useful. I have made no effort to
make it suitable for general consumption, but have found that a few people have
successfully used it to browse through the projects and find out all sorts of
things of their own accord.

Hot spots

Meanwhile, several programs have been made exploring these ideas, both
commercially and academically. Most of them use "hot spots" in documents, like
icons, or highlighted phrases, as sensitive areas. touching a hot spot with a
mouse brings up the relevant information, or expands the text on the screen to
include it. Imagine, then, the references in this document, all being
associated with the network address of the thing to which they referred, so
that while reading this document you could skip to them with a click of the
mouse.

"Hypertext" is a term coined in the 1950s by Ted Nelson [...], which has
become popular for these systems, although it is used to embrace two different
ideas. One idea (which is relevant to this problem) is the concept:
"Hypertext": Human-readable information linked together in an unconstrained
way.

The other idea, which is independent and largely a question of
technology and time, is of multimedia documents which include graphics, speech
and video. I will not discuss this latter aspect further here, although I will
use the word "Hypermedia" to indicate that one is not bound to text.

It has been difficult to assess the effect of a large hypermedia system
on an organisation, often because these systems never had seriously large-scale
use. For this reason, we require large amounts of existing information should
be accessible using any new information management system.

CERN Requirements

To be a practical system in the CERN environment, there are a number of
clear practical requirements.

Remote access across networks.

CERN is distributed, and access from remote machines is essential.

Heterogeneity

Access is required to the same data from different types of system
(VM/CMS, Macintosh, VAX/VMS, Unix)

Non-Centralisation

Information systems start small and grow. They also start isolated and
then merge. A new system must allow existing systems to be linked together
without requiring any central control or coordination.

Access to existing data

If we provide access to existing databases as though they were in
hypertext form, the system will get off the ground quicker. This is discussed
further below.

Private links

One must be able to add one's own private links to and from public
information. One must also be able to annotate links, as well as nodes,
privately.

Bells and Whistles

Storage of ASCII text, and display on 24x80 screens, is in the short
term sufficient, and essential. Addition of graphics would be an optional extra
with very much less penetration for the moment.

Data analysis

An intriguing possibility, given a large hypertext database with typed
links, is that it allows some degree of automatic analysis. It is possible to
search, for example, for anomalies such as undocumented software or divisions
which contain no people. It is possible to generate lists of people or devices
for other purposes, such as mailing lists of people to be informed of changes.
It is also possible to look at the topology of an organisation or a project,
and draw conclusions about how it should be managed, and how it could evolve.
This is particularly useful when the database becomes very large, and groups of
projects, for example, so interwoven as to make it difficult to see the wood
for the trees.

In a complex place like CERN, it's not always obvious how to divide
people into groups. Imagine making a large three-dimensional model, with people
represented by little spheres, and strings between people who have something in
common at work.

Now imagine picking up the structure and shaking it, until you make some
sense of the tangle: perhaps, you see tightly knit groups in some places, and
in some places weak areas of communication spanned by only a few people.
Perhaps a linked information system will allow us to see the real structure of
the organisation in which we work.

Live links

The data to which a link (or a hot spot) refers may be very static, or
it may be temporary. In many cases at CERN information about the state of
systems is changing all the time. Hypertext allows documents to be linked into
"live" data so that every time the link is followed, the information is
retrieved. If one sacrifices portability, it is possible so make following a
link fire up a special application, so that diagnostic programs, for example,
could be linked directly into the maintenance guide.

Non requirements

Discussions on Hypertext have sometimes tackled the problem of copyright
enforcement and data security. These are of secondary importance at CERN, where
information exchange is still more important than secrecy. Authorisation and
accounting systems for hypertext could conceivably be designed which are very
sophisticated, but they are not proposed here.

In cases where reference must be made to data which is in fact
protected, existing file protection systems should be sufficient.

Specific Applications

The following are three examples of specific places in which the
proposed system would be immediately useful. There are many others.

Development Project Documentation.

The Remote procedure Call project has a skeleton description using
Enquire. Although limited, it is very useful for recording who did what, where
they are, what documents exist, etc. Also, one can keep track of users, and can
easily append any extra little bits of information which come to hand and have
nowhere else to be put. Cross-links to other projects, and to databases which
contain information on people and documents would be very useful, and save
duplication of information.

Document retrieval.

The CERNDOC system provides the mechanics of storing and printing
documents. A linked system would allow one to browse through concepts,
documents, systems and authors, also allowing references between documents to
be stored. (Once a document had been found, the existing machinery could be
invoked to print it or display it).

The "Personal Skills Inventory".

Personal skills and experience are just the sort of thing which need
hypertext flexibility. People can be linked to projects they have worked on,
which in turn can be linked to particular machines, programming languages,
etc.

The State of the Art in Hypermedia

An increasing amount of work is being done into hypermedia research at
universities and commercial research labs, and some commercial systems have
resulted. There have been two conferences, Hypertext '87 and '88, and in
Washington DC, the National Institute of Standards and Technology (NST) hosted
a workshop on standardisation in hypertext, a followup of which will occur
during 1990.

The Communications of the ACM special issue on Hypertext contains many
references to hypertext papers. A bibliography on hypertext is given in
[NIST90], and a uucp newsgroup alt.hypertext exists. I do not, therefore, give
a list here.

Browsing techniques

Much of the academic research is into the human interface side of
browsing through a complex information space. Problems addressed are those of
making navigation easy, and avoiding a feeling of being "lost in hyperspace".
Whilst the results of the research are interesting, many users at CERN will be
accessing the system using primitive terminals, and so advanced window styles
are not so important for us now.

Interconnection or publication?

Most systems available today use a single database. This is accessed by
many users by using a distributed file system. There are few products which
take Ted Nelson's idea of a wide "docuverse" literally by allowing links
between nodes in different databases. In order to do this, some standardisation
would be necessary. However, at the standardisation workshop, the emphasis was
on standardisation of the format for exchangeable media, nor for networking.
This is prompted by the strong push toward publishing of hypermedia
information, for example on optical disk. There seems to be a general consensus
about the abstract data model which a hypertext system should use.

Many systems have been put together with little or no regard for
portability, unfortunately. Some others, although published, are proprietary
software which is not for external release. However, there are several
interesting projects and more are appearing all the time. Digital's "Compound
Document Architecture" (CDA) , for example, is a data model which may be
extendible into a hypermedia model, and there are rumours that this is a way
Digital would like to go.

Incentives and CALS

The US Department of Defence has given a big incentive to hypermedia
research by, in effect, specifying hypermedia documentation for future
procurement. This means that all manuals for parts for defence equipment must
be provided in hypermedia form. The acronym CALS stands for "Computer-aided
Acquisition and Logistic Support).

There is also much support from the publishing industry, and from
librarians whose job it is to organise information.

What will the system look like?

Let us see what components a hypertext system at CERN must have. The
only way in which sufficient flexibility can be incorporated is to separate the
information storage software from the information display software, with a well
defined interface between them. Given the requirement for network access, it is
natural to let this clean interface coincide with the physical division between
the user and the remote database machine.

This division also is important in order to allow the heterogeneity
which is required at CERN (and would be a boon for the world in general).

Fig 2. A client/server model for a distributed
hypertext system.

Therefore, an important phase in the design of the system is to define
this interface. After that, the development of various forms of display program
and of database server can proceed in parallel. This will have been done well
if many different information sources, past, present and future, can be mapped
onto the definition, and if many different human interface programs can be
written over the years to take advantage of new technology and standards.

Accessing Existing Data

The system must achieve a critical usefulness early on. Existing
hypertext systems have had to justify themselves solely on new data. If,
however, there was an existing base of data of personnel, for example, to which
new data could be linked, the value of each new piece of data would be
greater.

What is required is a gateway program which will map an existing
structure onto the hypertext model, and allow limited (perhaps read-only)
access to it. This takes the form of a hypertext server written to provide
existing information in a form matching the standard interface. One would not
imagine the server actually generating a hypertext database from and existing
one: rather, it would generate a hypertext view of an existing database.

Fig 3. A hypertext gateway allows existing data to be seen in
hypertext form by a hypertext browser.

Some examples of systems which could be connected in this way are

uucp News

This is a Unix electronic conferencing system. A server for uucp news
could makes links between notes on the same subject, as well as showing the
structure of the conferences.

VAX/Notes

This is Digital's electronic conferencing system. It has a fairly
wide following in FermiLab, but much less in CERN. The topology of a conference
is quite restricting.

CERNDOC

This is a document registration and distribution system running on
CERN's VM machine. As well as documents, categories and projects, keywords and
authors lend themselves to representation as hypertext nodes.

File systems

This would allow any file to be linked to from other hypertext
documents.

The Telephone Book

Even this could even be viewed as hypertext, with links between
people and sections, sections and groups, people and floors of buildings,
etc.

The unix manual

This is a large body of computer-readable text, currently organised
in a flat way, but which also contains link information in a standard format
("See also..").

Databases

A generic tool could perhaps be made to allow any database which uses
a commercial DBMS to be displayed as a hypertext view.

In some cases, writing these servers would mean unscrambling or
obtaining details of the existing protocols and/or file formats. It may not be
practical to provide the full functionality of the original system through
hypertext. In general, it will be more important to allow read access to the
general public: it may be that there is a limited number of people who are
providing the information, and that they are content to use the existing
facilities.

It is sometimes possible to enhance an existing storage system by coding
hypertext information in, if one knows that a server will be generating a
hypertext representation. In 'news' articles, for example, one could use (in
the text) a standard format for a reference to another article. This would be
picked out by the hypertext gateway and used to generate a link to that note.
This sort of enhancement will allow greater integration between old and new
systems.

There will always be a large number of information management systems -
we get a lot of added usefulness from being able to cross-link them. However,
we will lose out if we try to constrain them, as we will exclude systems and
hamper the evolution of hypertext in general.

Conclusion

We should work toward a universal linked information system, in which
generality and portability are more important than fancy graphics techniques
and complex extra facilities.

The aim would be to allow a place to be found for any information or
reference which one felt was important, and a way of finding it afterwards. The
result should be sufficiently attractive to use that it the information
contained would grow past a critical threshold, so that the usefulness the
scheme would in turn encourage its increased use.

The passing of this threshold accelerated by allowing large existing
databases to be linked together and with new ones.

A Practical Project

Here I suggest the practical steps to go to in order to find a real
solution at CERN. After a preliminary discussion of the requirements listed
above, a survey of what is available from industry is obviously required. At
this stage, we will be looking for a systems which are future-proof:

portable, or supported on many platforms,

Extendible to new data formats.

We may find that with a little adaptation, pars of the system we need
can be combined from various sources: for example, a browser from one source
with a database from another.

I imagine that two people for 6 to 12 months would be sufficient for
this phase of the project.

A second phase would almost certainly involve some programming in order
to set up a real system at CERN on many machines. An important part of this,
discussed below, is the integration of a hypertext system with existing data,
so as to provide a universal system, and to achieve critical usefulness at an
early stage.

(... and yes, this would provide an excellent project with which to try
our new object oriented programming techniques!) TBL March 1989, May 1990